Sponge cloths based on regenerated cellulose with mechanical reinforcement of fibres and/or a web are known (see EP 2 368 936 A2). Dry sponge cloths of this type are relatively hard, those with web reinforcement can even break as a result of bending. Consumers prefer the relatively soft, prewetted sponge cloths over the dry hard ones. Moreover, these have relatively more volume and a soft feel. For this, the sponge cloths are generally treated with an aqueous solution of a hygroscopically acting salt, in particular with a magnesium chloride solution. However, a disadvantage of such prewetted sponge cloths is their tendency towards mould infestation, particularly if they are in an air-tight film pack. In order to counteract this, prewetted sponge cloths have hitherto been finished with a biocide. This substance is generally added here to the magnesium chloride solution. The magnesium chloride, as well as some of the biocide, are washed out upon using the sponge cloth for the first time. Nevertheless, the presence of such an active ingredient, or more generally of a biocide, will in future have to be noted on the sales packaging of the sponge cloth. This may constitute a sales hindrance. Moreover, the use of biocides in sponge cloths has to be approved, there being a considerably restrictive tendency for approval.
DE 296 18 058 U1 discloses sponge cloths which are produced by the viscose process and which are provided with a biocide. Also known is a sterilization of dry sponge cloths with gamma rays or peroxides.